Telkes is known for creating the first thermoelectric power generator in 1947, designing the first solar heating system for the Dover Sun House in Dover, Massachusetts, (built entirely with solar heating, with the architect Eleanor Raymond[2][3] and the first thermoelectric refrigerator in 1953 using the principles of semiconductor thermoelectricity.

She was a prolific inventor of practical thermal devices, including a miniature desalination unit for use on lifeboats, which used solar power and condensation to collect potable solar still. The still saved the lives of airmen and sailors who would have been without water when abandoned at sea.[1]

One of her specialties were phase-change materials, including molten salts to store thermal energy. One of her materials of choice was Glauber's salt.

Telkes is considered one of the founders of solar thermal storage systems, earning her the nickname "the Sun Queen".[4] She moved to Texas in the 1970s and consulted with a variety of start-up solar companies, including Northrup Solar, which subsequently became ARCO Solar, and eventually BP Solar. She has a lot of schools named after here like, "Maria Telkes" in south Carolina, "telkes middle school" in San Francisco.Also Telkes Maria's high school" in Ohio